Hey guys this is due tomorrow and i need with number 5 its too tricky for me so can u plz

Use factorization or complete the quadratic forms to solve the problem

If you use the factorization,
x² + 3x = 40
move all terms to the left side, so the right side is equal to 0
x² + 3x - 40 = 0
two factors of -40 is 8 and -5
x² + 8x - 5x - 40 = 0
(x² + 8x) - (5x + 40) = 0
x(x + 8) - 5 (x + 8) = 0
(x - 5)(x + 8) = 0
x = 5 or x = -8

If you use completing quadratic forms
x² + 3x = 40
I multiply the two sides by 4 to make a complete quadratic forms
4x² + 12x = 160
add both side with 9
4x² + 12x + 9 = 160 + 9
(2x + 3)² = 169
(2x + 3)  = + √169 or (2x + 3) = -√169

∴ 2x + 3 = 13
   2x = 10
     x = 5
∴ 2x + 3 = -13
   2x = -16
     x = -8

THE SOLUTION
x = 5
x = -8